mRNA vaccine manufacturing – challenges in plasmid DNA cloning vector design

Abstract

In the post-COVID-19 era, there has been a significant increase in the development of mRNA vaccines not only against various diseases besides SARS-CoV-2, but also to treat cancer and genetic disorders. These vaccines, revolutionizing vaccinology, offer rapid pandemic response, high efficacy, minimal side effects, and cost-effectiveness. Achieving these benefits hinges on seamlessly integrating mRNA production steps, from plasmid DNA cloning to lipid nanoparticle formulation. This overview aims to comprehend or circumvent pitfalls in plasmid DNA cloning, a critical initial step in mRNA vaccine production. The focus is on achieving accurate insert sequence and gene expression, and it highlights the critical role of plasmid DNA design in ensuring vaccine effectiveness. Our research project entitled “Role of macroautophagy in lipid nanoparticle mRNA delivery and adjuvanticity” recognized the significance of this aspect. During our research, we designed a plasmid DNA cloning vector to incorporate the GFP-SARS-CoV-2 Spike gene. The vector was carefully constructed with several key features, including a high-copy plasmid, pUC18/pUC19 vector backbone with a robust T7 promoter, origin of replication, multiple cloning sites, polyadenylation signal, and ampicillin resistance for bacterial selection. Despite careful design, challenges like poly-A tail deletion may arise, prompting the exploration of stable large-size and low-copy vectors, as well as linear and bacteriophage vectors. But, for largescale production and regulatory compliance, vector systems must be scalable and well-documented. Commercial vectors and automated synthesis facilitate gene construction, with artificial intelligence ensuring sequence accuracy. Precision is crucial for complex antigens, as seen in tuberculosis mRNA vaccine development. Addressing these challenges demands a combining of molecular biology techniques, computational tools, and collaboration with experts in microbiology, molecular biology, and vaccine development. The design’s scalability and documentation are vital for large-scale production and regulatory compliance, emphasizing the multifaceted approach required for successful mRNA vaccine development.